After the “Shadow Brokers” hacker group leaked NSA files exposing a number of previously unknown vulnerabilities in Microsoft Windows last week, the company told customers not to worry. Most of the bugs have already been fixed, and a handful of others only apply to unsupported, pre-Windows 7 versions of the operating system, Microsoft said.

As Engadget reports, some of the security holes were patched only last month, suggesting Microsoft may have been tipped off to the leak by either the NSA or the hackers (who may have charged the company for the privilege). Microsoft sometimes credits researchers who reported vulnerabilities in its products, but in this case, the company has stayed mum on how it learned of the bugs. SM